Twitter type microblog application

I'm looking for someone to create a scalable open source Twitter-type microblog application. I'm not requesting a Twitter clone. I am asking for a developer who can create a customized and fully-functional microblog API with Twitter-type features, including hash tags, individual logins and a CMS feature up to 140 characters. The app must also allow users to upload videos and other file types, including sound files. It should also allow users to import their social network connections, for example, Twitter, Linked In, Facebook and My Space. The finished product will be outsourced to an appropriate hosting [login to view URL] is important. I want the application to scale well. If the project is done right (meaning that people can easily use use it) there might be additional work. There are lots of opportunities. I will use an escrow service for payment.